Treatment of artificial materials



Nov. 13, 1934. w A, DICK"; Er AL 1,980,191

TREATMENT OF ARTIFICIAL MATERIALS Filed May 7, 1931 COTTON BACKINGMATERIAL \wlevd urs Patented Nov. 13,1934

UNITED STATES PATENT OFFICE TREATMENT OF ARTIFICIAL MATERIALS WilliamAlexander Dickie and Frank Brentnall Hill, Spondon, near Derby, England,assignors to Celanese Corporation of America, a corporation of DelawareApplication May 7, 1931, Serial No. 535,806 In Great Britain July 14,1930 14 Claims.

the material while leaving the remainder intact.

Thus for example materials containing wool and cellulose may be treatedwith sulphuric acid or other suitable reagent so as to convert thecellulose into hydrocellulose without affecting the wool. After asuitable heat treatment the hydrocellulose may then be removed bymechanical means, for example by brushing. Again mixed materialscontaining wool and silk may be treat- 15 ed with steam at hightemperatures in such a way that after drying the wool can be rubbed to afine powder and so removed, the silk being unaffected. Processes such asthese are known by the general term of carbonizing processes. The methodof carbonization has found many useful applications in the textile art.Thus, for example, it provides a method of removing cotton fromadmixture with wool or wool from admixture with silk in shoddy or otherwaste materials. Further it provides a valuable means of obtainingpattern effects. A pile fabric, for example, may be treated so as toremove selected portions of the pile while leaving the backing materialand the remainder of the pile unaffected. Again embroidery may be workedupon a suitable backing material which may subsequently be removed by aprocess of carbonization which does not affeet the embroidery itself. Bytreating fabrics woven from mixed yarns with a. carbonizing agentcapable of removing one constituent of the mixture without affecting theother, gauzes may be obtained. Moreover the production of these effectsis not confined to the treatment of mixed materials; the effects may beproduced upon materials, the fibres of which are all of the samechemical nature by the application of suitable resists to selectedportions thereof.

According to the present invention we treat materials consisting of orcontaining organic de- "rivatives of cellulose and in particularcellulose acetate with a treating agent comprising an organic liquid andan inorganic salt having a solvent or latent solvent action on thecellulose derivative, so as to attack at least art of the cellulosederivative without affecting he remainder of the material, andsubsequently drying the material and removing the cellulose derivativeattacked by suitable means.

The invention is particularly applicable to materials consisting of orcontaining cellulose acetate but it may also be applied with valuableresults to materials comprising other organic derivatives of cellulose,for example cellulose formate, propionate or butyrate and ethyl, methylor benzyl cellulose.

The best results appear to be obtained when the organic liquid is itselfa solvent for the cellulose derivative. Thus in the case of materialscomprising cellulose acetate the best results appear to be obtained whenan organic liquid consisting of or containing acetone is employed.

Excellent results may however be obtained by the use of methyl or ethylalcohol or other swelling agents for the cellulose acetate. Among thesolvents or swelling agents with which good results have been obtainedmention may be made of: diacetone alcohol, acetic acid, phenol, benzylalcohol or cyclohexanol. When a low boiling liquid is employed it may beof advantage to add thereto a high boiling substance having solvent orlatent solvent properties for the cellulose derivative, e. g. triacetin,in order to reduce the rate of evaporation. The organic liquid employedwill naturally be selected having due regard to the particular inorganicsolvent or swelling agent to be used and should be capable of dissolvingthe latter.

The inorganic swelling agent or solvent is preferably a metallicthiocyanate. Calcium thiocyanate has been found particularly suitableand 35 excellent results are obtained by the application to the materialof a solution of this salt in acetone or methylated spirit. Otherinorganic salts which may also be employed with advantage include sodiumthiocyanate,'potassium thiocyanate 99 and zinc chloride.

The treating liquid may be applied to the material by any suitablemeans, for example by printing, stencilling, padding, or immersion ofthe material in a bath containing the solvent liquid, as may be mostconvenient to obtain the particular effect required. A part of thematerial may if so desired be treated in such a way as to resist theaction of the treating liquid, e. g. by the application of a suitableresist.

The treating agent may be applied in any suitable form, for example inthe form of a liquid which may or may not contain suitable thickeningagents, or in paste form.

After subjection to the action of the treating agent, the material ispreferably dried, for example in an air oven or stove at a temperatureof about 100 to C. When thoroughly dry the part of the material affectedby the treating agent is removed by suitable means, for example bybrushing. When the solution contains a thiocyanate the removal of thematerial attacked is best effected immediately after drying, otherwiseon account of the deliquescent nature of thiocyanates, difficulty may beexperienced in removing the material cleanly in the places requiredwithout affecting the remaining portions of the material.

The process of the invention may be applied to produce a large number ofvaluable efiects among which may be mentioned, the removal of fibres oforganic derivatives of cellulose from admixture with other fibres inwaste materials, the production of gauzes by the treatment of fabricswoven from mixedyarns of organic derivatives of cellulose and otherfibres whether of animal, vegetable or 'artificial origin, the removalof a backing consisting of an organic derivative of cellulose from anembroidery, and in particular, the production of pattern effects,especially upon pile or other fabrics.

Such pattern effects may be obtained by local application of thetreating agent by any suitable means. We may instance the application bymeans of suitably engraved printing rolls or stencils, of a 50% solutionof calcium thiocyanate in methylated spirits containing 5% of olive oilsoap to a velvet having a pile of cellulose acetate upon a backing ofnon-cellulose derivative material, for example cotton, regeneratedcellulose or silk. The swelling solution is preferably applied to theback of the fabric which is then heated in a stove at to C. until quitedry, when the affected portions of the cellulose acetate may be removedby brushing. Instead of applying a swelling solution to the back of thefabric it may be applied to the pile, which may if so desired be treatedlocally with suitable resists.

Coloured effects may be produced by the application of suitabledyestuffs or colouring agents in conjunction with the carbonizingprocess. For instance, when treating a cellulose acetate pile fabrichaving a backing of cotton or regenerated cellulose, the pile may at anystage in the process be printed or otherwise coloured by the applicationof a suitable colouring agent therefor, for example an S. R. A.dyestuif, while the backing may be printed or otherwise coloured by theapplication of a colouring agent having an aflinity for cellulose, forexample adirect cotton dye.

After the material has been dried and treated so as to remove thegreater part of the affected material, it is preferably subjected to ascouring treatment in order to remove any of the swelling solutionremaining together with any of the affected material which has not beenremoved by the mechanical treatment. It is also of advantage to scourthe materials thoroughly before the application of the swelling solutionin order to remove any grease present which might interfere with theprocess. When the solvent liquid contains a thiocyanate it is advisableto prevent contamination of the material with iron, but should a redcolouration result owing to such contamination it may readily be removedby means of sulphur dioxide.

The effects produced in cellulose acetate pile fabrics treated accordingto the present inven-- tion are illustrated in the accompanying drawing,wherein Fig. 1 represents a pile fabric woven with a cotton backing 1and a celluloseacetate pile 2, from which fabric portions of the pilehave been removed in the shaded areas, and

contact with the material.

Fig. 2 shows a sectional view along the line 22 of Fig. 1.

The following examples illustrate without in any way limiting theinvention.

Example 1 A solution is made by dissolving 50 parts by weight of calciumthiocyanate in 50 parts by weight of acetone. This solution is thenapplied by means of a printing block of the requisite design or in anyother suitable manner, to the back of the fabric. The fabric may have acotton back and a pile of cellulose acetate yarn or any other similarcellulose derivative, and should be scoured before treatment to removeany dirt or grease that may prevent the solution coming in The treatedfabric is then placed in an oven or stove maintained at a uniformtemperature between 100 and 110 C. until thoroughly dry. The treatedpile is then removed by lightly brushing the fabric. This operationshould be performed either in the stove or immediately on removal owingto the deliquescent nature of calcium thiocyanate which renders removalof the pile diflicult after exposure to the air for any time. The fabricis then rescoured. Any discolouration produced by contact with iron maybe removed by treatment with sulphur dioxide or other suitable bleachingagent;

Example 2 A solution is made by dissolving 50 parts by weight ofammonium thiocyanate in 50 parts by weight of acetone to which is added5 parts by Weight of diacetone alcohol. This solution is then 110applied in a similar manner to the method described in Example 1.

Example 3 A solution is prepared by dissolving 100 parts by weight ofcalcium thiocyanate in 100 parts by weight of methylated spirits towhich is added one part by weight of olive oil soap.

This solution is then applied to the back of the fabric, having a cottonback and a pile preferably of cellulose acetate or any other similarcellulose derivative, by means of a printing block, or stencil of therequisite design or by any other suitable means, the fabric having beenpreviously scoured. As some precipitation of the soap may take place onaccount of the presence of the calcium thiocyanate care should be takenthat the solution is agitated before. use.

The treated fabric is then dried in a stove maintained at 100-110 C. andimmediately on removal or even in the stove itself, the fabric isbrushed to remove the treated pile. The fabric may then be finished asdescribed in Example 1.

What we claim and desire to secure by Letter Patent is:-

1.'Process for the treatment of textile materials containing organicderivatives of cellulose, which comprises treating at least a part ofthe organic cellulose derivative with a solution in a volatile organicliquid of an inorganic salt having a swelling action upon the cellulosederivative, and causing the organic liquid to evaporate until thetreated material is in a solid condition and capable of removal bybrushing.

2. Process for the treatment of textile materials containing organicderivatives of cellulose, which comprises treating at least a part ofthe organic cellulose derivative with a solution of an inorganic salt ina volatile liquid, the said-salt and organic liquid each having at leasta swelling action upon the cellulose derivative, and causing the organicliquid to evaporate until the treated material is in a solid conditionand capable of removal by brushing.

3. Process for the treatment of textile materials containing celluloseacetate, which comprises treating at least a part of the celluloseacetate with a solution in a volatile organic liquid of an inorganicsalt having a swelling action upon the cellulose acetate, and causingthe organic liquid to evaporate until the treated material is in a sglidcondition and capable of removal by brush- 4. Process for the treatmentof textile materials containing cellulose acetate, which comprisestreating at least a part of the cellulose acetate with a solution of aninorganic salt in a volatile liquid, the said salt and organic liquideach having at least a swelling action upon the cellulose acetate, andcausing the organic liquid to evaporate until the treated material is ina solid condition and capable of removal by brushing.

5. Process for the treatment of textile materials containingacetone-soluble cellulose acetate,.

which comprises treating at least a part of the cellulose acetate with asolution of calcium thiocyanate in acetone, causing the acetone toevaporate until the treated material is in a solid condition and capableof removal by brushing, and thereafter removing the cellulose acetateaffected.

6. Process for the treatment of textile materials containingacetone-soluble cellulose acetate, which comprises treating at least apart of the cellulose acetate with a solution of a metallic thiocyanatein acetone containing a relatively nonvolatile solvent for the celluloseacetate, and causing the liquid constituents to evaporate until thetreated material is in a solid condition and capable of removal bybrushing, and thereafter removing the cellulose acetate afiected.

7. Process for the treatment of textile materials containingacetone-soluble cellulose acetate, which comprises treating at least apart of the cellulose acetate with a solution of ammonium thiocyanate inacetone containing diacetone alcohol, causing the liquid constituents toevaporate until the treated material is in a solid condition and capableof removal by brushing, and thereafter removing the cellulose acetateaffected.

8. Process for the treatment of textile materials containing organicderivatives of cellulose, which comprises treating at least a part ofthe organic cellulose derivative with a solution in a volatile organicliquid of an inorganic salt having a swelling actionTipon the cellulosederivative, and subsequently drying the material at a temperaturebetween 100 and 110 C. to render the treated material capable of removalby brush- 9. Process for the treatment of textile materials containingorganic derivatives of cellulose, which comprises treating at least apart of the organic cellulose derivative with a solution in a volatileorganic liquid of an inorganic salt having a swelling action upon thecellulose derivative together with a soap, and causing the organicliquid to evaporate until the treated material is in a solid conditionand capable of removal by brushing.

10. Process for the treatment of textile materials containing celluloseacetate, which comprises treating at least a part of the celluloseacetate with a solution in a volatile organic liquid of an inorganicsalt having a swelling action upon the cellulose acetate together with asoap, and causing the organic liquid to evaporate until the treatedmaterial is in a solid condition and capable of removal by brushing.

11. Process for the production of pattern effects upon textile materialscontaining cellulose acetate, which comprises locally treating thecellulose acetate with a solution in a volatile organic liquid of aninorganic-salt having a swelling action upon the cellulose acetate,causing the organic liquid to evaporate until the treated material is ina solid conditionand capable of removal by brushing, and thereafterremoving the cellulose acetate affected.

12. Process for the production of pattern effects upon textile materialscontaining acetonesoluble cellulose acetate, which comprises treatingthe cellulose acetate locally with a solution of calcium thiocyanate inacetone, causing the acetone to evaporate until the treated material isin a solid condition and capable of removal by brushing, and thereafterremoving the cellulose acetate afiected.

13. Process for the production of pattern effects upon textile materialscontaining acetone-v soluble cellulose acetate, which comprises treatingthe cellulose acetate locally with a solution of ammonium thiocyanate inacetone containing a relatively non-volatile solvent for celluloseacetate, causing the liquid constituents to evaporate until the treatedmaterial is in a solid condition and capable of removal by brushing, andthereafter removing the cellulose acetate affected.

14. Process for the production of pattern effects upon textile-materialscontaining cellulose acetate, which comprises treating the celluloseacetate locally with a solution in a volatile organic liquid of aninorganic salt having a swelling action upon the cellulose acetate,drying the material at a temperature between 100 and 110 C. to renderthe treated material capable of removal by brushing, and thereafterremoving the cellulose acetate afiected.

WILLIAM ALEXANDER DICKIE. FRANK BRENTNALL HILL.

